Automotive vehicles commonly include power supply systems for providing voltage regulation and powering vehicle electrical systems. Increasingly, power supply systems are employed for use in charging electric and hybrid vehicles and powering the electrical systems of such vehicles. Power supply systems designed for use in charging electric and hybrid vehicles and powering vehicle systems require precise control of the output voltage at the power supply terminals.
Power supply systems, including those for use in automotive vehicles, are well known in the art. An exemplary power supply system is shown in U.S. Pat. No. 6,459,247 entitled “Power Supply Capable Of Being Configured To Generate Positive And Negative Output Resistances.” Examples of automotive power supply systems, as well as various features thereof, are shown in U.S. Pat. No. 7,279,805 entitled “Vehicle Power Supply System With A Series Regulator” and in U.S. Pat. No. 7,506,182 entitled “Vehicle Mounted Power Supply System.”
To control the voltage output at the endpoint of a power supply interconnect cable in order to meet necessary accuracy, prior art power supplies have required sense leads at the interconnect output point. Such sense leads, however, are expensive and difficult to package. They can also cause a power supply to have lower reliability. In that regard, if the sense leads break or are cut, the power supply will not regulate. The use of sense leads also makes the power supply more sensitive to noise.
An alternative to the use of sense leads is to increase the size of the interconnect cable by using thicker, lower resistance wire. With sufficiently thick, low resistance wire, the voltage drop can be made lower at the output point of the interconnect cable than the voltage precision requirement for a particular application. Significantly, however, such a design adds both cost and weight to the interconnect cable and the power supply system.
There exists a need, therefore, for a system and method for controlling an output voltage of a power supply that would address various problems of prior art systems and methods. Such a system and method would eliminate the use of sense leads at the output point of the power supply interconnect cable, but without the use of thicker, lower resistance wire in the interconnect cable to do so. Such a system and method would instead compensate for voltage drop on a power supply interconnect cable, thereby decreasing costs while maintaining or improving reliability in the operation of a vehicle power supply system.